There are many applications in health care that require prolonged direct contact between skin and tape or fabric. For example, adhesive tape is widely used to secure gauze bandages to a specific portion of the skin, such as a wound site. Self-contained adhesive bandages are mass-marketed for similar use. Special applications such as therapeutic patches for intradermal drug delivery also require intimate contact between fabric or tape and the skin.
Conventional tapes or fabrics trap moisture vapor between the skin and the tape and can cause maceration of the skin. Skin maceration is a condition of softening and separation of the skin from connecting tissue caused by wetting or steeping. Maceration contributes to a prolonged healing time, is uncomfortable to the user and often results in loss of adhesion between the skin and the adhesive applied to the tape at a point where the tape meets the skin.
It is desirable for tapes and fabrics used in health care applications to be waterproof in order to keep foreign material including viruses and bacteria away from the skin and accompanying wound site and also to provide a dry environment for expedited healing of the wound. However, conventional waterproof tapes and backings are usually made of polyvinyl chloride and polyethylene. Although these materials are waterproof they have the disadvantage of trapping moisture, i.e., they are non-breathable. Moisture vapor generated by the skin is unable to evaporate or dissipate because the fabric or tape seals the vapor between the tape and skin. This moist environment prolongs healing time and results in maceration.
Numerous attempts have been made to overcome these disadvantages, for example by providing a porous material which allows water vapor to escape. Porosity is generally achieved by providing macroscopic holes or pores in the tape or fabric. Although this increases breathability, waterproofness is lost.
To reduce the incidence of maceration and thereby reduce healing time it is desirable to provide a tape or fabric which is both waterproof and breathable. At the same time, the tape or fabric must be hypoallergenic for use in health care products.
A waterproof, breathable fabric has previously been developed having a multifilament nylon fabric substrate of 220 denier, 40.times.40 count, coated with a first layer of a mixture of ethyl and butyl acrylate and a second layer of microporous polyester urethane coated onto the first layer. Although this fabric is somewhat waterproof and breathable, the nylon, nonabsorbent substrate fabric cannot be used as a tape or fabric in health care applications. This fabric is not suitable for prolonged, direct contact with skin because the nylon substrate used has a low attractive capillarity; hence it is non-moisture absorbent and therefore does not pass moisture vapor through the acrylic and polyurethane layers as effectively as an absorbent substrate. This fabric is useful in rainwear garments (for example) where prolonged, direct contact with skin does not occur. Use of the fabric in applications involving prolonged direct contact with skin would result in maceration of the skin.
It is an object of the present invention to provide a fabric capable of prolonged, direct contact with skin which is waterproof, breathable, non-macerating and hypoallergenic.